Dissolved gas sampling and analysis has been increasing in regularity so potential effects of fracturing activity in wells can be monitored. Traditionally, bags and plastic bottles are used to collect water for determining dissolved gas, such as methane, ethane, and propane, in the water samples. The type of container used can depend on the type of data needed from a sample. Both containers (bags and bottles) generally provide a sufficient sample for chemical and isotopic analysis of dissolved gas for identifying the source of the gas. If the amount of gas in the water is to be quantified to ppm or cc/L, the type of container needed may depend on the amount of gas present.
A dissolved gas bottle can be used to quantify the amount of gas in the water if the gas content is below saturation at atmospheric pressure (i.e., does not form bubbles). A bag is preferred when the amount of gas in the water is above the saturation limit because both the dissolved gas and the free gas are quantitatively collected.
A dissolved gas bottle is designed to collect samples from domestic water wells, and the bottle can hold about 1-liter, which makes it large enough for compositional and isotopic analysis of the dissolved gas. The bottle has a cap-mounted septum so it is not necessary to open the bottle during analysis, which reduces the potential for contamination of the sample. Each bottle also contains a bactericide capsule to prevent degradation of the gas.
FIG. 1 illustrates a sample bag 10 according to the prior art. This bag 10 resembles the IsoBags® available from Isotech Laboratories, Inc. of Champaign, Ill. (ISO BAG is a registered trademark of Isotech Laboratories, Inc.) The bag 10 consists of a film pouch 12, which can come with a bactericide capsule 14 inside to prevent degradation of the sample. A spout 20 is permanently affixed inside a side hole in the pouch 12 using retaining rings, gaskets, or other permanent fixtures. The spout 20 also includes a self-closing type of valve 22, such as a luer valve used for medical purposes and available from Qosina Corp. of New York.
Although the existing bottles and bags are suitable for taking domestic water samples to determine dissolved gas, sampling technicians are continually striving for a more versatile sampling container that can be readily used in the field and handled in the lab.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.